Automotive coatings and coatings are divided into two parts: OEM furnace and Refinish repairs. Which are somewhat different from each other in terms of usage and basic formulation.
OEM automotive resins are designed for automotive coating spraying lines that have automatic spraying systems and conveyor ovens, and their resin base is selected based on the coating curing at an oven temperature of 145 degrees Celsius. In repair automotive coating, the resins used are selected based on air-dryness or two-component polyurethane 2K.
Definitely, the hardness, gloss and chemical resistance of OEM colors are higher than Refinish, and in the production and design of repair colors, we always try to make the most similar properties to the color of the original body.
The process of coatinging a car chassis from the beginning is that the raw metal body enters the degreasing pool through the conveyor line, which contains soda-based detergents with (PH: 11) so that the fats and grease caused by pressing are completely washed. Of course, spray washing is another degreasing method that washes the inside of the car in the form of high pressure showers. After degreasing, the rinsing step and detergent neutralization is done, in this step, the rinsing solution has inhibitors that prevent rusting of the car body, if the degreasing is done well, the body enters the PT stage by the conveyor, the PT stage, includes dicationic and tricationic zinc phosphate, which can be done by both spraying and immersion, the zinc phosphide solution contains large amounts of 2-valent and 3-valent zinc phosphates, and amounts of catalyst that in the presence of air oxygen blowing during the reaction, with direct electric current DC leads to a kind of oxidation and reduction in the surface of the iron body of the car and with this action it gives phosphate on the chemical bond with the surface of the body, this layer will be about 5 micron, the advantage of phosphating is that it guarantees the stickiness of the lining layer. After phosphating, a rinsing and drying stage is performed again, then the zinc phosphate body enters the ED pool, ED (electrodeposition) is a type of high-solid base water liner that has dielectric properties, mainly basic ED liner resins are from the blocked amino acrylic family and sometimes based on blocked amine epoxy with low molecular weight and have anti-corrosion pigments with dielectric properties. As a result of the electric current inside the ED solution in the immersion tank, the whole body has The negative charge and the body electrode of the tank have a positive charge and due to this electric current, the ED lining material migrates to the iron body of the car and sticks to it, the body is mostly in motion for 15 minutes in the ED tank and after It goes into a 145°C oven for 25 minutes to fully bake the ED liner under heat. After ED and body cooling, the conveyor enters the lining line, each line has a cell, inside the special cell, there are two types of automatic spraying systems, the older system called 7Bell and the newer system called 4robot, the furnace lining of the car is mainly based on alkyd resin or melamine polyester modified with epoxy polyisocyanate, In general, all OEM coatings must have some polar and non-polar solvents that have electrical resistance (Resistivity) between 100 and 150 microsiemens in order to be able to spray with electrostatic liquid coating spraying systems. That’s why, the furnace lining of a car also has this feature and is sprayed by automatic spraying to a wet film thickness of 60 micron, and again the body enters the oven at 145 degrees Celsius for 25 minutes, and finally it delivers a dry film of 45 lining micron, After the lining stage, the body enters the metallic or solid base coat spraying line by conveyor. OEM base coat colors are similar to metallic repair coating in terms of formulation, and both are based on saturated polyester resins, but they are slow drying and suitable for ovens, and the size of aluminum used in them must be below 20 micron and also have an electrical resistance of 120 micro Siemens, the base coat coating is sprayed by a robot or Seven Bell with a film thickness of 15 to 25 micron, and after going through the aerating path and blowing fresh air, which is called flash-off and directly Enters the spraying phase of top coat clear. At this stage, the automotive clear, which is mainly based on melamine-based thermostatic acrylic resins, is done by automatic spraying, and after going through the oven with a temperature of 145 degrees Celsius for 30 minutes, it gives a dry film of 35 to 50 micron. In general, in a factory original body of a car, the overall thickness of the coating is always 80 to 100 micron on the vertical surfaces and 90 to 140 micron on the horizontal surfaces of the body.
In repair automotive coatings, due to the absence of the above conditions, the use of repair coatings changes, because in this case, our intention is only to repair a piece of the body or a specific piece of it for corrosion protection, as well as beauty and matching with the original body.
Rangin Kimia Company, relying on the technical knowledge and experience of personnel who have been working in the field of OEM automotive coatings for years, has started its production of repair automotive coating under the Kimia brand since 2016 and offers a variety of products with the best quality and competitive prices in the market.
The steps of body repair are as follows: firstly, after smoothing, the first step of corrugation is done by the coatinger by applying polyester filler putty, Polyester filler putty is based on unsaturated polyester resins with various fillers, which are hardened by a 2% paste-like hardener called benzoyl peroxide, in this situation, the master can use multi-purpose gray and cream colored putty of Rangin Kimia in POWER brand, Automotive polyester filler putty must have several features at the same time, Power polyester filler putty has a very strong stickiness on white galvanized sheet, iron, aluminum and fiberglass. Flexibility up to a thickness of 200 micron is one of the best features of this product and it gives the coatinger enough opportunity to scratch resolve on smooth and curved surfaces because its gelling property does not depend on the ambient temperature and soft scratch resolving is one of the most popular features of this product, About three hours after applying the polyester filler putty, the coatinger can sand and polish the power putty and then do the rest of the steps. One of the problems that the coatinger will always face is the effect of yellowing or heating or the yellowing of polyester filler putty to higher layers, which is caused by incomplete formulation and poor quality of putty raw materials, in Power polyester filler putty, the customer does not see this problem at all.
After planishing with polyester filler putty, the coatinger applies an ester layer, automotive liners are marketed as one-component instant and two-component polyurethane.
Kimia’s instant automotive iron liners are based on specialized alkyd resins and stuck to iron and galvanized with high coverage in three colors: gray, cream, and white, according to customer reports; in hot and cold weather, Kimia’s instant liners offer a favorable and stable behavior in stickiness to the body in hot and cold weather and the smoothness of the coating particles will ultimately lead to an acid cure matte uniform surface, and this feature will improve the final quality of the base coat and the final clear for the master.
2k partial polyurethane liners with the Kimia brand are produced as high solid and can be used with general hardener at a ratio of 4:1. It has much higher flexibility than instant liners.
Kimia’s high solid polyurethane primer is marketed with two codes: white P021 and gray P020. ” Kimia ” repair polyurethane primer works like Poly Omid epoxy primer and in addition to providing a smooth and sticky surface, it protects the metal against salt and moisture over time, just like the ED furnace original lining, Today, professional coatingers use Kimia’s P020 gray polyurethane primer after planishing, and after 12 hours, they spray a layer of the same color instant primer. It can be a metallic instant primer of the same color as the base coat, the advantage of the same color primer is that it reduces the amount of base coat coating used.
After the following steps, the spraying of the metallic base coat color begins. The base coat color is known as the 54 and 69 colors in the market, it is called the base coat based on solid color and aluminum glitter powder 54, and the pearlescent shell base is called 69. Unlike instant nitrocellulose coating, basecoat coating has no yellowing properties at all, because it is based on saturated polyester and is made in one-component and air-dry form by auxiliary resins based on vinyl celluloses.
Usually, half an hour after applying the base coat, the coatinger can apply the final layer or clear coat. Kimia brand 2k automotive clears are marketed in three application levels with code HS 982, HS 921 and MS 901, the difference between these clears is in the amount of solid or final dry film and their anti-wear.
In car OEM white colors, it is mainly sold in two coats by the car manufacturer, in this way, a white base coat with a specific RAL code is sprayed and then a kiln coat is applied, In the repair market, this is very difficult, because the difference between the color and the body will be very obvious, and the double coating method is only used for the shells of imported cars. In the Iranian market, for solid coatings, 2K two-component polyurethane coating based on hydroxy acrylic resin and aliphatic polyisocyanate hardener is used, which is called 21, the most popular 21 color product of the ” Kimia” brand is called AC 60, which has a very pure and snowy whiteness, which always satisfies customers with its glossy finish. And it is also produced in three solid color codes for domestic cars. In addition, light resistance, resistance to moisture and atmospheric conditions, the 21 white color of “Kimia” brand is very high compared to other manufacturers, and this stability of quality is due to the use of special types of specialized raw materials in its production.
All Kimia automotive coatings can be used on the car bumper, and the best PP plastic liner in the market with the ability to resist the car wash test is produced by the Kimia brand with the code PP 619, On this lining, you can use polyester filler putty, instant linings and the same color as well, and all these capabilities are due to the accurate analysis of the market needs by experts, and we have introduced a new definition of quality that we must always go beyond the customer’s needs.
Production and collection: Rangin Kimia Industrial Complex
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